XANTUS'S HUMMINGBIRD 449 



wbite oak trees, which, especially the latter, are much more abundant than 

 the live oaks, but discovered no nests. Nearly all the nests found were hung 

 at the ends of small twigs, from four to six feet from the ground, in very 

 small live oaks. Two exceptions were nests found twelve feet up in large 

 oaks. * * * 



The nesting material of the Comondu birds and the Laguna birds was about 

 the same, the nests being composed of fine plant down, dried flower heads, 

 plant fibers and small feathers, all bound together with spider webbing. A 

 nest from Comondu is covered on the outside with strips of bark of the water 

 willow. Without exception all the nests of the Sierra birds are beautifully 

 decorated with lichens from the oaks. The Comondu birds do not decorate 

 their nests with lichens, these not being available, but sometimes they do 

 attempt ii little decoration with bits of bark or leaves. 



The nesting dates of the Laguna birds are also different from those at 

 Comondu. We arrived in the Sierra de la Laguna on June 16 and remained 

 until July 7, and in that time no nests were found, though I am not sure that 

 the birds were not nesting. August 3 I re-visited the mountains and remained 

 in Laguna Valley and vicinity until September 3, and in this month discovered 

 twenty-five nests. On September 1 I found a nest just ready for eggs. Of 

 those found, the greater number contained young or heavily incubated eggs, 

 so it might be said that the nesting season in Laguna Valley started about the 

 middle of July and continued to the middle of September. 



Mr. Brewster (1902) gives the following detailed description of a 

 nest, found by Mr. Frazar: 



A nest found at San Jose del Rancho, on July 28, was placed at the extremity 

 of a slender, drooping oak twig, about eight feet above the ground. One side 

 is built against and around the main stem (here only .12 inches in diameter), 

 and the bottom rests securely on a terminal fork, from the ends of which 

 hang a number of dry, bleached oak leaves, apparently of the previous year's 

 growth. The chief, if not only, material composing the walls of this nest 

 consists of small, woolly leaves of a pale sage-green color, inteimixed with 

 reddish-brown, catkin-shaped objects, which appear to be made up of numerous 

 minute seed vessels attached in double, triple, or quadruple rows or clusters 

 to stems an inch or more in length. The entire outer surface of the nest is 

 wrapped with a net-work of spider-web silk so fine as to be well-nigh invisible 

 but suflBciently strong and taughtly drawn to give the walls a firm, smooth 

 outline. The interior is not lined save at the bottom, which is furnished with a 

 soft bed of whitish down, evidently that of some bird. This nest measures 

 externally 1.60 inches in diameter by 1.65 in depth ; internally, .73 inches in 

 diameter by .50 in depth. 



Eggs. — The two eggs laid by Xantus's hummingbird are prac- 

 ticalljr indistinguishable from those of other hummingbirds of sim- 

 ilar size. They are pure dull white and vary in shape from oval to 

 elliptical-oval. The measurements of 26 eggs average 12.3 by 8.4 

 millimeters ; the eggs showing the four extremes measure 13.5 by 9.9, 

 11.4 by 7.8, 1.9 by 7.5 millimeters. 



Plumages. — I have no information on the early plumages of the 

 nestling, but in the juvenal plumage, which is probably fully ac- 

 quired before the young bird leaves the nest, the sexes are apparently 



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